Pneumatic Die Grinder Operable as Blow Gun

ABSTRACT

A pneumatic grinding tool having a blower feature that can be selectively employed to blow debris away from a work area. The tool has a valve that directs input air that can be used to drive an output of the tool to a blower air passage. The blower air passage terminates at a head of the near the output of the tool.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Provisional Application No. 60/973,359, filed Sep. 18, 2007, the entirety of which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to die grinders and, more specifically, to a die grinder tool having an air blower accessory.

Powered die grinders such as pneumatic die grinders rotate an output member with a grinder head, such as a burr, for smoothing, shaping, and/or polishing metal surfaces. In general, pneumatic die grinders have a cylindrical housing designed to be held in a user's hand such that the user's fingers engage a trigger lever pivotally secured at a lower portion of the housing. In this way, the user can easily operate the grinder (i.e., depress the trigger lever) by squeezing the trigger lever with her fingers.

SUMMARY OF THE INVENTION

In one aspect of the present invention a pneumatic grinding tool generally comprises a housing, an output member rotatably secured to the housing and a main air inlet for delivering pressurized air into the housing. An air motor in the housing includes an air rotor operably connected to the output member. The air rotor is housed in an interior chamber of the air motor adapted for selective fluid communication with the air inlet for receiving pressurized air from the air inlet to impart rotational movement of the air rotor. A blower passage in the housing has an exit opening leading outside the tool and located adjacent to the output member. The blower passage is adapted for selective fluid communication with the main air inlet independently of the interior chamber for directing a flow of pressurized air from the air inlet out of the housing via the exit opening of the blower passage.

In another aspect of the present invention, a pneumatic die grinder generally comprises a housing, an output member rotatably secured to the housing and a main air inlet for delivering pressurized air into the housing. An air motor disposed in the housing includes a rotor operably connected to the output member. A blower passage in the housing has an outlet opening leading outside the tool. The tool is selectively configurable to operate in a grinder mode, in which air entering the housing from the main air inlet will be directed to the rotor of the air motor to drive the output member, and a blow-gun mode, in which air entering the housing from the main air inlet will be directed to the blower passage and out the tool through the outlet opening of the blower passage.

Other objects and features will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of one embodiment of a die grinder of the present invention;

FIG. 2 is a longitudinal section of the die grinder in a grinder mode;

FIG. 2A is a partial section of the die grinder in a blow gun mode taken in the plane including line 2A-2A of FIG. 1, showing a knob of a diverter valve in full lines and removing components of the diverter valve for clarity;

FIG. 3 is an exploded perspective of the die grinder;

FIG. 4 is a front end elevation of a housing of the die grinder;

FIG. 5A is a longitudinal section of the housing taken in the plane including line 5A-5A of FIG. 4;

FIG. 5B is a longitudinal section of the housing taken in the plane including line 5B-5B of FIG. 4

FIG. 6 is a rear end elevation of the housing;

FIG. 7 is a rear perspective of a motor assembly of the die grinder;

FIG. 8 is an exploded front perspective of the motor assembly;

FIG. 9 is a longitudinal section of the motor assembly;

FIG. 10 is a side elevation of the motor assembly with passages in the motor assembly being illustrated by hidden lines;

FIG. 11 is an exploded view of a collar assembly of the die grinder;

FIG. 12 is an axial section of the collar assembly;

FIG. 13 is an enlarged, fragmentary portion of the section of FIG. 2;

FIG. 14 is an exploded view of a diverter valve of the die grinder;

FIG. 15 is a fragmentary section of the die grinder with the diverter valve positioned in a first position; and

FIG. 16 is a fragmentary section of the die grinder with the diverter valve positioned in a second position.

Corresponding reference characters indicate corresponding parts throughout the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, one embodiment of a pneumatic die grinder constructed according to the principles of the present invention is generally indicated throughout the drawings by reference numeral 10. Referring to FIGS. 1-3, in general, the die grinder of the illustrated embodiment includes a cylindrical housing 12 (FIGS. 1 and 2) having front and rear ends and a longitudinal axis A1 extending therebetween. A collar assembly, generally indicated at 16, secures an air motor, generally indicated at 18 (FIGS. 2 and 3), inside axial blind bore 20 extending through the front end of the housing 12. An air hose connector 22 for delivering pressurized air into the housing 12 and an exhaust deflector 26 for directing spent air from the air motor 18 are secured to the rear end of the housing. A diverter valve, generally indicated at 28, for directing pressurized air within the housing 12, as will be explained in detail below, is secured in a transverse through bore 30 extending generally transverse to the longitudinal axis A1. A dial, generally indicated at 32 (broadly, a handle), for actuating rotation of the diverter valve 28 is secured to a first end of the valve by a pin 34. A trigger 38 generally adjacent to a second, opposite end of the diverter valve 28 is pivotally secured to the housing 12 by a pin 40. A rubber outer cover 42 is molded over the housing 12 to provide a comfortable grip for the user.

Referring to FIGS. 2-6, a main air inlet opening 44 extends axially from the rear end of the housing 12 to the transverse through bore 30. The air hose adaptor 22 threads into the main air inlet opening 44 (FIGS. 2 and 3). First and second outlet openings 48, 50, respectively, extend longitudinally through the housing 12 from the transverse through bore 30 to the axial blind bore 20 in the front of the housing. The outlet openings 48, 50 are spaced apart along the circumference of the transverse through bore 30 and are in selective fluid communication with the diverter valve 28, as will be described in detail below. A blind bore 51 (FIG. 4) or use in aligning the motor assembly 18 in the housing 12, as will be explained, extends longitudinally from the closed end of the axial blind bore 20. As shown in FIGS. 5 and 6, the housing 12 also includes a pair of diametrically opposed, generally oblong exhaust openings 54 extending longitudinally through the housing from the closed end of the axial blind bore 20 through the rear end of the housing. The exhaust openings 54 direct spent air from the air motor 18 toward the exhaust deflector 26 and out of the housing 12. The exhaust openings 54 are fluidly connected to each other via an arcuate channel 56 extending along the rear of the housing 12 between the exhaust openings. The housing 12 may be machined from a single metal casting, such as an aluminum casting. Other ways of forming the housing 12 are within the scope of the present invention.

Referring to FIGS. 2 and 7-10, the air motor 18 includes a rotatable shaft 60 and an air rotor 62 integrally formed with the shaft and secured in a motor casing, generally indicated at 64, which includes a cylindrical sleeve 65. The air rotor 62 includes a plurality of retractable vanes (not shown) extending radially outward around a circumference of the shaft 60. Front and rear portions of the shaft 60 are secured in ball bearings 66A, 66B in respective front and rear end caps 70A, 70B of the air motor casing 64. Together, the sleeve 65 and the front and rear end caps 70A, 70B define an interior chamber 71 (FIG. 9) of the casing 64 in which the air rotor 62 is retained. The vanes of the rotor 62 drive rotation of the shaft 60 when pressurized air is introduced into the interior chamber 71 of the motor casing 64, and the ball bearings 66A, 66B allow the shaft to rotate about a rotational axis A2 of the shaft. An elongate pin 72 extends through aligned openings 74 (FIG. 8) in the sleeve 65 and the end caps 70A, 70B (the opening in the front end cap 70A is hidden in FIG. 8) to fixedly secure the sleeve and the end caps together. As shown best in FIGS. 7 and 10, a portion of the pin 72 extends rearward from the rear end cap 70B. As will be discussed below, inserting the pin 72 into the locator blind bore 51 properly positions the motor assembly 18 in the axial blind bore 20 of the housing 12.

An output member 78 of the grinder 10 is threaded on the front portion of the motor shaft 60 so that a rotational axis of the output member is coincident with the rotational axis A2 of the shaft. The illustrated die grinder 10 is of the type generally referred to in the art as a straight die grinder because the rotational axis of the output member 78 is generally coincident with the longitudinal axis A2 of the housing. It is understood that the die grinder may be of other types, such as a die grinder including an output member having a rotational axis that is offset a fixed or selectively adjustable angle (e.g., 90 degrees or 120 degrees) from the longitudinal axis of the housing. As shown best in FIG. 9, a collet 80 is received in an axial cavity 82 of the output member 78. The collet 80 has a radially expandable axial opening 84 for receiving a stem of a bit (not shown), such as a burr bit. A locking collar 86 threadably secured to the free end of the output member 78, radially compresses the collet 80 around the stem of the bit to secure the bit to the output member.

Referring to FIGS. 11-13, the collar assembly 16 that retains the air motor 18 in the grinder housing 12 includes radially inner and outer collar members, generally indicated at 90, 92, respectively. The outer collar member 92 includes a beveled front face 94 and a rearwardly extending annular skirt 96. The inner collar member 90 is concentrically received in a central, axial opening 98 of the outer collar member 92 and includes a generally cylindrical body 100 threaded into the axial blind bore 20 in the front end of the housing 12. As shown in FIG. 13, an annular flange 102 extending radially outward from a front portion of the inner collar member 90 presses an annular ledge 106 extending radially inward in the central opening 98 of the outer collar member 92 against the front end of the housing 12 so that the outer collar member is rotatably secured to the front end of the housing. An O-ring 110 (FIGS. 11 and 12) is disposed between the flange 102 of the inner collar member 90 and the annular ledge 106 of the outer collar member 92 to form an air-tight seal between the members. A second O-ring 112 (FIGS. 11 and 12) sits in a circumferential groove 114 in the interior surface of the outer collar member 92 that is spaced axially from the inner annular ledge 106. As shown in FIG. 13, the second O-ring 112 engages a front end margin 120 of the outer cover 42 to create a sliding air-tight seal between the skirt 96 of the outer collar member 92 and outer cover. The front end margin 120 of the cover 42 has a reduced thickness which, together with the circumferential groove 114, maintains the O-ring in sealed contact with the cover. The output member 78 extends through an axial through bore 116 in the inner collar member 90. The front end cap 70A of the motor casing 64 is partially received in a counter-bore 118 of the inner collar member 90 and abuts a front wall 120 of the counter-bore.

For purposes explained below, an inner through bore 124 extends generally radially through the body 100 of the inner collar member 90. An outer through bore 126 (broadly, a blower exit opening) extends generally radially through the outer collar member 92 from the interior of the skirt 96 through the beveled front face 94 of the outer collar member. The outer radial through bore 126 extends through the outer collar member 90 at an angle with respect to the longitudinal axis A2 of the housing 12, although it is understood that the outer radial through bore may extend generally parallel to the longitudinal axis A2 of the grinder housing 12. In the illustrated embodiment, the outer radial through bore 126 extends at about a 30 degree angle with respect to the longitudinal A2 axis of the grinder housing 12. In other embodiments, through bore 126 may extend at other angles with respect to the axis A2. In one embodiment the through bore 126 extends at an angle of about 30 to 60 degrees. In another embodiment the through bore 126 extends at an angle of less than 90 degrees. As shown in FIG. 13, the radial through bores 124, 126 are in fluid communication with each other via an annular plenum 130 defined by the interior of outer collar member 92 and the front end of the housing 12. Although the inner and outer radial through bores 124, 126 in the drawings are generally aligned longitudinally for purposes of illustration, the openings remain in fluid communication regardless of the rotational position of the outer radial bore.

Referring back to the motor assembly 18, and in particular to FIGS. 7-10, when the motor assembly received in the housing 12, an oblong opening 130A in the rear end cap 70B is generally aligned with and fluidly connected to an opening 130B in the sleeve 65 that extends into the interior chamber of the motor casing 64. The openings 130A, 130B together constitute a first passage in the air motor casing 64. The opening 130A in the rear end cap 70B is also aligned with and fluidly connected to the second outlet 50 in the housing 12 (FIG. 2). Together, the first passage of the air motor casing 64 (i.e., the openings 130A, 130B) and the second opening 50 in the housing 12 constitute a motor air passage in the illustrated embodiment, communicating with the interior chamber 71 of the casing 64.

A second passage in the motor casing 64 is defined by an opening 134A in the rear end cap 70B, an opening 134B extending longitudinally through the cylindrical wall of the motor casing sleeve 65, and an opening 134C in the front end cap 70A (FIGS. 7, 8 and 10). The second air passage, more specifically the opening 134B, does not extend into the interior chamber 71 of the casing 64 and is not fluidly connected to the rotor 62. Instead, the opening 134B extends longitudinally through the cylindrical wall of the sleeve 65. The opening 134A in the rear end cap 70B, and thus the second passage, is fluidly connected to the first outlet opening 48 in the housing 12 that extends from the transverse through bore 30. As shown in FIGS. 2A and 13, the opening 134C in the front end cap 70A, and thus the second passage, is aligned with and fluidly connected to the inner radial through bore 124 in the inner collar member 90 secured to the front end of the grinder housing 12. Together, the first inlet opening 48, the second passage in the motor casing 64 (i.e., the openings 130A, 130B, 130C), the inner radial through bore 124 in the inner collar member 90, the annular plenum 130 in the collar assembly 16, and the outer through bore 126 in the outer collar member 92 constitute a blower air passage in the illustrated embodiment. Other ways of forming a blower air passage that extends from the diverter valve 28 to outside the grinder 10 is within the scope of the invention.

Referring to FIG. 7, front and rear exhaust openings 138A, 138B, respectively, extend radially through the sleeve 65 of the motor casing 64. The exhaust openings 138A, 138B allow spent air to exit the interior space of the casing 64. An exhaust channel 140 formed in the exterior surface of the sleeve 65 extends longitudinally between the front and rear exhaust openings 138A, 138B, respectively. The rear cap 70B has a pair of diametrically opposed exhaust channels 142 formed in the exterior surface. Each of the exhaust channels 142 is generally aligned with and fluidly connected to one of the diametrically opposing exhaust openings 54 in the housing 12. An arcuate groove 144 in the rear end cap 70B fluidly connects the opposing exhaust channels 142 in the rear cap. The exhaust channels 140, 142 in the sleeve 65 and the rear end cap 70B, respectively, and the interior wall of the housing 12 together constitute an exhaust passage that fluidly connects the radial exhaust openings 138A, 138B in the sleeve to the pair of diametrically opposed exhaust openings 54 in the housing.

Referring to FIGS. 14-16, the diverter valve 28 received in the transverse through bore 30 of the housing 12 includes a cylindrical rotor 150 having an axial passage 152 extending between the opposite first and second ends. The rotor 150 is rotatable in the transverse through bore 30 about a rotational axis A3 (FIG. 15) that is generally transverse to the rotational axis A1 of the housing 12. Two axially spaced apart O-rings 154A, 154B, 154C received in circumferential grooves in the exterior surface of the rotor 150 sealingly engage the housing 12 in the transverse bore 30 to prevent air from leaking out of the housing through the transverse through bore.

As briefly stated above and described in more detail below, the dial 32 of the diverter valve 28 is secured to the first end of the rotor 150 to actuate rotation of the rotor. The dial 32 takes the form of a knob 156 and an integrally formed cylindrical projection 158 extending outward from the knob and into the first end of the rotor 150. The pin 34 extends through aligned radial openings 160, 162 in the cylindrical projection 158 and the rotor 150, respectively, to secure the dial 32 to the rotor. An O-ring 166 received in a circumferential groove in the exterior surface of the projection 158 sealingly engages the interior wall of the rotor 150 to prevent air from leaking out the first end of the rotor. The knob 156 of the dial 32 and an annular stop 168 projecting radially outward from the second end of the rotor 150 that engages the exterior surface of the housing 12 retains the rotor 150 in the transverse through bore 30.

The valve rotor 150 has a motor-inlet port 170 and a blower-inlet port 172 spaced apart circumferentially along the rotor 150. As shown in FIGS. 2 and 15, the motor-inlet port 170 is aligned with, at least partially, and fluidly connected to the main air inlet opening 44 in the housing 12 when the rotor 150 is selectively rotated to a first position. When the rotor 150 is in the first position and the motor-inlet port 170 is fluidly connected to the air inlet opening 44, an outlet port 174 of the rotor is at least partially aligned with and fluidly connected to the second opening 50 in the housing 12, and thus pressurized air passing through the valve 28 is directed to the interior of the air motor casing 64 to drive the motor shaft 60.

Likewise, as shown in FIG. 16, the blower-inlet port 172 is aligned with, at least partially, and fluidly connected to the main air inlet opening 44 when the rotor 150 is selectively rotated to a second position. When the rotor 150 is in the second position and the blower-inlet port 172 is at least partially aligned with and fluidly connected to the main air inlet opening 44, the outlet port 174 of the rotor 150 is at least partially aligned with and fluidly connected to the first outlet opening 48 in the housing 12 and thus is fluidly connected to the blower passage so that pressurized air passing through the valve 28 is directed out the grinder 10 through the outer opening 126 in the outer collar member 92. Through this configuration, the grinder 10 is configurable between a grinder mode, where the grinder is operable as a grinder, and a blow gun mode, where the grinder is operable as a blow gun so that the user can blow debris and shavings away from a workpiece using the grinder. In the illustrated embodiment, when the motor-inlet port 170 is fluidly connected to the main air inlet opening 44, the blower-inlet port 172 is blocked from fluid connection with the main air inlet opening 44, and vice versa, so that the dual operations of die grinder 10 as a die grinder and a blow gun are mutually exclusive.

In the illustrated embodiment, the diverter valve 28 is also configured to allow a user to control the rotational speed of the output member 78 by further selective rotation (i.e., adjustment) of the valve rotor 150 when the rotor is in its first position and operating as a grinder. The effective open area of the motor-inlet port 170 through which air can pass into the rotor 150, and eventually to the motor 18, is contingent on the degree to which the main air inlet opening 44 is offset from the motor-inlet port. Moreover, the effective open area of the second outlet opening 50 through which air can pass into the motor passage and into the motor 18 is contingent on the degree to which the outlet port 174 of the rotor 150 is offset from the second outlet opening.

At a “Hi” position, the relationship between the effective open areas of the motor-inlet port 170 and the second outlet opening 50 is such that the greatest amount of air is able to pass into and through the rotor 150 to the motor to drive the motor at its highest speed. By rotating the valve rotor 150 (clockwise in the illustrated embodiment) from its “Hi” position to a “Low” position, the effective open areas of the motor-inlet port 170 and the second outlet opening 50 continually decreases until the amount of air from the air inlet port entering the motor casing is at its least amount. In the illustrated embodiment, continuing to rotate the rotor 150 past the “Low” position will position the rotor in its second position whereby the blower-inlet port 170 will be aligned with the main air inlet 44 and the outlet port 174 of the rotor will be aligned with and fluidly connected to the first outlet opening 48 and the blower air passage.

Speed indicia (not shown), e.g., the words “Hi” and “Lo”, is provided on the rubber outer cover 42, and arrow or other indicia is provided on the knob 156 of the dial 32. Together, the arrow and the speed indicia indicate the rotational position of the rotor 150 necessary to selectively change or maintain the rotational speed of the output member 78 when the grinder 10 is operating as a die grinder. The rotor is in the first position when the arrow is pointing toward or anywhere between the “Hi” and “Lo” indicia. The outer cover 42 also has suitable indicia (not shown) to be used with the arrow indicia 182 on the knob 156 (see, FIG. 2A) to indicate the rotational position (i.e., the second position) of the rotor 150 necessary to change operational mode of the grinder 10 from a grinder mode to a blow gun mode, and vice versa.

Referring again to FIGS. 14-16, an air-intake valve, generally indicated at 190, is disposed within the axial passage 152 of the rotor 150 of the diverter valve 28 to allow the user to selectively control operation of the grinder 10, whether the grinder is in its grinder mode or its blow gun mode. The air-intake valve 190 includes a disk shaped stopper 192 positioned in the rotor 150 downstream of the motor-inlet port 170 and the blower inlet-port 172 and upstream of the outlet port 174. A reduced interior diameter in the rotor 150 forms a valve seat 194 upstream of the outlet port 174 of the rotor toward which the stopper 192 is biased by a compression spring 196 to block air flow to the outlet port. An O-ring 198 received in a circumferential groove in the exterior surface of the stopper 192 sealingly engages the valve seat 194 when the valve component is seated on the seat.

A plunger 200 extends axially through the second end of the rotor 150. One end of the plunger 200 is received in a cavity 202 in the stopper 192. The plunger 200 is slidable along the axis A3 of the rotor 150 to unseat the stopper 192 and allow air to flowing into the rotor to flow out the outlet port 174 and into one of the motor air passage and the blower air passage, as explained above. Sliding movement of the plunger 200 is actuated by the squeezing the trigger 38 so that the trigger pivots toward the housing 12 about the pin 40. The trigger 38 includes a safety stop 204 pivotally attached to the trigger by a pin 20. The safety stop 204 is selectively pivotable between a spring-biased position, in which the stop extends generally transverse to the trigger 38 and prevents pivotal movement of the trigger toward the housing 12, and a different position, in which the stop extends generally parallel to the trigger and allows the trigger to be pivoted toward the housing to actuate axial, sliding movement of the plunger 200.

Referring to FIG. 2, the air-intake adaptor 22 has a first end threadably secured in the main air inlet opening 44, and a second end with internal threads for threadably receiving a quick-connect, air hose connector (not shown). The air hose connector is connectable to an air hose of a source of pressurized air to deliver pressurized air into the housing 12.

Referring to FIGS. 2, 2A and 15-17, the exhaust deflector 26 surrounds the air-intake adaptor 22 and is rotatable about a rotational axis that is generally coincident with the longitudinal axis A1 of the grinder housing 12. The air-intake adaptor 22 extends axially through the exhaust deflector 26 so that a radially extending annular flange 210 of the adaptor engages the exhaust deflector to secure the deflector in an axial recess 212 in the rear end of the housing 12. An O-ring 214 received in a circumferentially groove in the exhaust deflector 26 sealingly engages the housing 12 in the axial recess 212 to form an air-tight seal between the housing and the exhaust deflector. The interior wall of the air deflector 26 and the exterior surface of the air-intake adaptor 22A define an annular-shaped exhaust passage 218 fluidly connected to the pair of diametrically opposed exhaust openings 54 in the housing 12. An exit slot 220 extending radially through the exhaust deflector 26 in fluid connection with the annular passage 218 allows spent air flowing through the exhaust passage to exit the grinder 10. Because the exhaust deflector 26 is rotatable, the user can selectively change the direction of the flow of spent air exiting the grinder 10.

In use, the die grinder 10 of the illustrated embodiment may be used to grind or smooth a surface of an object, particular a surface of a die. A suitable die grinding member, such as a grinding burr (not shown), is secured to the output member 78 using the collet 80 in the manner detailed above. The quick-connect air hose connector (not shown) is secured to an air hose (not shown) of a source of pressurized fluid so that pressurized air flows into the main air inlet opening 44. With the diverter valve 28 selectively positioned in the first position so that arrow indicia on the knob 156 of the dial 32 is pointing toward either the “HI” or the “Lo” indicia or anywhere in between, the motor-inlet port 170 of the valve rotor 150 is fluidly connected to the main air inlet opening 44 and the elongated outlet port 174 of the valve rotor is fluidly connected to the motor passage (i.e., the second outlet opening 50, and the aligned openings 130A, 130B in the motor casing 64). This configuration is illustrated in FIGS. 2 and 15 of the drawings.

With the diverter valve 28 in the first position, squeezing the trigger 38 to move the plunger 200 and axially displace the stopper 192 of the air-intake valve 190 from its valve seat 194 delivers pressurized air from the main air inlet 44, through the motor-inlet port 170, the outlet port 174 and into the motor air passage formed by the second outlet opening 50 and openings 130A, 130B in the air motor casing 64. The pressurized air in the sleeve 65 rotates the rotor 62, the shaft 60, the output member 78 and the grinding member about the rotational axis A1. Spent air exits the motor sleeve 65 through the radial exhaust openings 138A, 138B and travels rearward through the exhaust passage defined by the channel in the air motor sleeve 65 and the channels 142 in the rear end cap 70B, through the exhaust openings 54 in the grinder housing 12, through the annular exhaust passage 218 and out the grinder 10 through the exhaust deflector 26. During operation, the rotational speed of the output member 78 can be adjusted by selectively rotating the valve rotor 150 using the knob 156, as described in detail above.

After grinding the surface of the object for a certain period of time, whereby shavings are produced, the valve rotor 150 is selectively rotated using the knob 156 so that the arrow indicia on the knob points toward the blow-gun indicia on the outer cover 42. This configuration is illustrated in FIGS. 2 and 16. FIG. 16 shows the grinder 10 in longitudinal section in the same way as FIGS. 2 and 15. However, the section of FIG. 2 is rotated so that the communication of the outlet port 174 with the first outlet opening 48 and the reminder of the blower air passage can be seen. The knob 156 has been left unsectioned in FIG. 2A for clarity in establishing the orientation of the grinder 10. As explained above and illustrated in FIGS. 2A and 16, at this point the valve rotor 150 is in the second position and the blower-inlet port 172 of the rotor is fluidly connected to the main air inlet opening 44, and the outlet port 174 of the rotor is fluidly connected with blower air passage (i.e., the first inlet opening 48, the second passage in the motor casing 64, i.e., the openings 134A, 134B, 134C, the inner through bore 124 in the inner collar member 90, the plenum 130 in the collar assembly 16, and the outer through bore 126 in the outer collar member 92).

With the grinder 10 in the blow gun mode, when the trigger 38 is depressed and the stopper 192 of the air-intake valve 190 is unseated, pressurized air flows from the main air inlet opening 44, through the blower-inlet port 172 and the outlet port 174 of the valve rotor 150 and into the blower passage. In the blower passage, the pressurized air flows through the motor casing 64 (i.e., the rear end cap 70B, the cylindrical wall of the sleeve 65 and the front end cap 70A), through the inner through bore 124 in the inner collar member 90, through the plenum 130 in the collar assembly 16, and through the outer through bore 126 in the outer collar member 92 to outside the grinder 10. The pressurized air flows out the outer through bore 126, in a generally forward direction that is angled (e.g., about 30 degrees) with respect to the longitudinal axis A1 of the grinder housing 12. While holding the grinder 10, the user manipulates the grinder so that the pressurized air flowing out of the blower passage blows the shavings off of the object and/or the work surface. The outer collar member 92 can be selectively rotated about the longitudinal axis A1 of the housing 12 to change the angular location of the outer through bore 126 and the direction at which pressurized air is flowing out of the blower passage.

When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

As various changes could be made in the above without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 

1. A pneumatic grinding tool comprising: a housing; an output member rotatably secured to the housing; a main air inlet for delivering pressurized air into the housing; an air motor in the housing and including an air rotor operably connected to the output member, the air rotor being housed in an interior chamber of the air motor adapted for selective fluid communication with the air inlet for receiving pressurized air from the air inlet to impart rotational movement of the air rotor; a blower passage in the housing having an exit opening leading outside the tool and located adjacent to the output member, the blower passage adapted for selective fluid communication with the main air inlet independently of the interior chamber for directing a flow of pressurized air from the air inlet out of the housing via the exit opening of the blower passage.
 2. A pneumatic grinding tool as set forth in claim 1 further comprising a diverter valve disposed downstream of the main air inlet and upstream of the air motor and the blower passage for selectively directing the pressurized air from the air inlet to at least one of the interior chamber of the air motor and the blower passage.
 3. A pneumatic grinding tool as set forth in claim 2 wherein the diverter valve is movable between a first position, in which pressurized air from the main air inlet is directed solely to the interior chamber of the air motor, and a second position, in which pressurized air from the main air inlet is directed solely to the blower passage.
 4. A pneumatic grinding tool as set forth in claim 3 wherein the diverter valve is rotatable with respect to the housing between said first position and said second position.
 5. A pneumatic grinding tool comprising: a housing; an output member rotatably secured to the housing; a main air inlet for delivering pressurized air into the housing; an air motor in the housing and including an air rotor operably connected to the output member, the air rotor being housed in an interior chamber of the air motor adapted for selective fluid communication with the air inlet for receiving pressurized air from the air inlet to impart rotational movement of the air rotor; a blower passage in the housing having an exit opening leading outside the tool and located adjacent to the output member, the blower passage adapted for selective fluid communication with the main air inlet independently of the interior chamber for directing a flow of pressurized air from the air inlet out of the housing via the exit opening of the blower passage; a diverter valve disposed downstream of the main air inlet and upstream of the air motor and the blower passage for selectively directing the pressurized air from the air inlet to at least one of the interior chamber of the air motor and the blower passage, the diverter valve being movable between a first position, in which pressurized air from the main air inlet is directed solely to the interior chamber of the air motor, and a second position, in which pressurized air from the main air inlet is directed solely to the blower passage, the diverter valve also being rotatable with respect to the housing between said first position and said second position and having a motor-inlet port for fluid connection to the main air inlet when the valve is in said first position, and a separate blower-inlet port for fluid connection to the main air inlet when the valve is in said second position, the motor-inlet port and the blower-inlet port being spaced apart along a circumference of the diverter valve.
 6. A pneumatic grinding tool as set forth in claim 5 wherein the diverter valve has an outlet port for fluid connection to the interior chamber of the air motor when the valve is in the first position, and for fluid connection to the blower air passage when the valve is in the second position.
 7. A pneumatic grinding tool as set forth in claim 6 further comprising an air-intake valve in the diverter valve for selectively regulating fluid communication between the outlet port and the motor-inlet and blower-inlet ports.
 8. A pneumatic grinding tool as set forth in claim 1 wherein the blower passage extends generally longitudinally through a motor casing defining the interior chamber of the motor toward the output member.
 9. A pneumatic grinding tool comprising: a housing; an output member rotatably secured to the housing; a main air inlet for delivering pressurized air into the housing; an air motor in the housing and including an air rotor operably connected to the output member, the air rotor being housed in an interior chamber of the air motor adapted for selective fluid communication with the air inlet for receiving pressurized air from the air inlet to impart rotational movement of the air rotor; a blower passage in the housing having an exit opening leading outside the tool and located adjacent to the output member, the blower passage adapted for selective fluid communication with the main air inlet independently of the interior chamber for directing a flow of pressurized air from the air inlet out of the housing via the exit opening of the blower passage, an angular position of the exit opening of the blower passage with respect to at least one of longitudinal axis of the housing and a rotational axis of the output member being selectively adjustable.
 10. A pneumatic grinding tool as set forth in claim 9 wherein the exit opening of the blower passage is generally adjacent to the output member.
 11. A pneumatic grinding tool as set forth in claim 10 wherein the exit opening extends at an angle with respect to the rotational axis of the output member of less than about 90 degrees.
 12. A pneumatic grinding tool as set forth in claim 10 wherein the exit opening extends at an angle with respect to the rotational axis of the output member of between about 30 degrees and about 60 degrees.
 13. A pneumatic grinding tool as set forth in claim 10 further comprising a collar assembly secured to the housing to retain the air motor in the housing, the collar assembly including a collar member freely rotatable about the longitudinal axis of the housing, wherein the exit opening extends through the rotatable member of the collar assembly.
 14. A pneumatic grinding tool as set forth in claim 13 wherein the collar member constitutes a first collar member, the collar assembly further including a second collar member engaging the first collar member to rotatably secure the first collar member to the housing, the second collar member having a through bore in fluid communication with the exit opening and constituting a part of the blower air passage.
 15. (canceled) 